MLSE balanced receiving method and device

Abstract

The invention provides an MLSE balanced receiving method and device, and the method comprises the steps: receiving a to-be-recovered signal formed by a signal transmitted at each moment, and enabling the to-be-recovered signal to be obtained through the channel transmission and noise addition of a transmitted signal; for each moment, comparing the state metrics for transferring each possible signal state at the previous moment to the signal state at the current moment, and determining a target state transfer path for transferring the signal state at the previous moment to the signal state at the current moment when the state metric is maximum, determining the signal state at the previous moment when the state measurement is maximum as the maximum possible signal state at the previous moment; and determining an equalization signal corresponding to the to-be-recovered signal based on the target state transition path at each moment and a signal state corresponding to a maximum state metric in the state metrics of each possible signal state at the last moment and each possible signal state at the last moment of each moment. According to the invention, the equalization complexity can be reduced.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to an MLSE equalization reception method and apparatus. Background Technology

[0002] With the rapid development of information technology, the demand for data transmission rates in high-speed link communication is increasing daily. Starting with single-channel 112Gbps, communication systems have widely adopted four-level pulse amplitude modulation (PAM) as the primary modulation method, and the latest Ethernet standard also specifies the continued use of PAM4 modulation at single-channel 224Gbps rates. However, with further increases in single-channel speeds, PAM4 modulation faces serious challenges, primarily due to its excessively high required sampling bandwidth, leading to severe inter-symbol interference (ISI). This not only increases the complexity of hardware implementation but also introduces technical instability risks.

[0003] To eliminate inter-symbol interference (ISI), more powerful equalization algorithms must be employed to enhance signal transmission quality. However, while traditional equalization algorithms improve performance, they also incur additional implementation costs, including increased chip area and prolonged processing latency. These costs often do not match the performance gains of the equalization algorithm, leading to a decrease in overall energy efficiency. Therefore, in high-speed communication scenarios of 224Gbps and above in a single channel, developing new equalization algorithms with higher energy efficiency is particularly important. These new equalization algorithms not only need to have good equalization performance but also need to maintain low complexity and power consumption in hardware implementation. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an MLSE equalization reception method and apparatus to eliminate or improve one or more defects existing in the prior art.

[0005] One aspect of the present invention provides an MLSE equalization reception method, the method comprising the following steps: The signal to be recovered is formed by receiving signals transmitted at various times, wherein the signal to be recovered is obtained by channel transmission and noise addition to the transmitted signals; For each time step, the state metrics of each possible signal state from the previous time step to the signal state at the current time step are compared to determine the target state transition path from the previous time step to the signal state at the current time step when the state metric is maximized. The signal state of the previous time step when the state metric is maximized is determined as the maximum possible signal state of the previous time step. Each possible signal state is determined based on the modulation scheme of the transmitted signal. Each state metric is updated based on the state metrics of each possible signal state at the previous time step and the corresponding state transition metrics. Each state transition metric is obtained based on the signal to be recovered, the channel coefficient, each possible signal state at the previous time step, and the signal state at the current time step. Based on the target state transition path at each time step, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of the possible signal states at the last time step, the equalization signal corresponding to the signal to be recovered is determined.

[0006] In some embodiments of the present invention, the state metrics of each possible signal state at the previous moment to the signal state at the current moment are compared to determine the target state transition path from the previous moment's signal state to the current moment when the state metric is maximum. The signal state at the previous moment when the state metric is maximum is determined as the maximum possible signal state at the previous moment, including: The state metrics of each possible signal state from the previous moment to the current moment are grouped in pairs, and the difference between the two state metrics of each group is compared to determine the signal state of the previous moment when the state metric of each group is larger. The state metrics of the signal state at the previous moment when the state metric of each group is larger are compared pairwise to determine the target state transition path from the signal state at the previous moment when the state metric is larger to the signal state at the current moment, and the signal state at the previous moment when the state metric is larger. The signal state at the previous time step is determined as the maximum possible signal state at the previous time step, so as to obtain the maximum possible signal state at each time step.

[0007] In some embodiments of the present invention, the state metrics for transferring each possible signal state from the previous moment to the current moment are grouped pairwise, and the differences between the two state metrics in each group are compared to determine the signal state in the previous moment when the state metric of each group is larger. This includes: The state metrics that transfer the signal state from the previous time step to the current time step are grouped into pairs, and the difference between the two state metrics in each group is calculated to obtain the difference between the two state metrics in each group. Based on the correspondence between the difference between the state metrics of the two possible signal states at the previous time and the signal state at the current time and the state transition conditions, determine each first state transition condition corresponding to the difference between the two state metrics of each group. Based on the mapping relationship between state transition conditions and state transition paths, determine each state transition path corresponding to each first state transition condition. Based on each state transition path, determine the signal state of the previous moment when the state metric of the signal state transitioning to the current moment is larger.

[0008] In some embodiments of the present invention, the state metrics of the signal state at the previous moment when the state metric of each group is larger are compared pairwise to determine the target state transition path from the signal state at the previous moment when the state metric is largest to the signal state at the current moment, and the signal state at the previous moment when the state metric is largest, including: For each group with a larger state metric, the state metric from the previous time step to the current time step is transferred by pairwise subtraction to obtain the difference between each pair of larger state metrics. Based on the correspondence between the difference between the state metrics of the two possible signal states transitioning to the signal state at the previous time and the state transition conditions, determine each second state transition condition corresponding to the difference between each of the two larger state metrics. By combining each first state transition condition and each second state transition condition, we obtain the state transition combination condition. Based on a preset lookup table, a state transition path matching the state transition combination conditions is determined, and the determined state transition path is used as the target state transition path. The lookup table includes multiple state transition combination conditions and multiple corresponding state transition paths. Based on the target state transition path, determine the signal state at the previous moment when the state metric of the signal state transitioning to the current moment is maximized.

[0009] In some embodiments of the present invention, the equalization signal corresponding to the signal to be recovered is determined based on the target state transition path at each time step, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of the possible signal states at the last time step, including: Based on the target state transition path at each time step and the signal state corresponding to the maximum state metric among the state metrics of each possible signal state at the last time step, the final signal state of the previous time step is determined by backtracking from the maximum possible signal state of the previous time step at each time step. Based on the final signal state of the previous time step and the signal state corresponding to the maximum state metric of the last time step, the equalization signal corresponding to the signal to be recovered is obtained.

[0010] In some embodiments of the present invention, the method further includes: If the number of determined signal states reaches a preset backtracking depth, an intermediate equalization signal is output, and the process of determining signal states continues until the final equalization signal is output. The intermediate equalization signal is determined by the signal state corresponding to the maximum state metric among the target state transition paths at each time step reaching the backtracking depth, the maximum possible signal state at the previous time step, and the state metrics of the possible signal states at the last time step.

[0011] In some embodiments of the present invention, the signal state at each time moment includes each possible signal state, the modulation method includes pulse amplitude modulation, and the state metric and the state transition metric are calculated by simplifying the Euclidean distance expansion between the signal to be recovered and the transmitted signal obtained through channel transmission.

[0012] In some embodiments of the present invention, the method further includes: demapping the equalization signal to obtain the corresponding recovery signal.

[0013] Another aspect of the present invention provides an MLSE equalization receiving apparatus, the apparatus comprising: a computer device including a processor and a memory, the memory storing computer instructions, the processor executing the computer instructions stored in the memory, and the system implementing the steps of the aforementioned method when the computer instructions are executed by the processor.

[0014] Another aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the aforementioned method.

[0015] Another aspect of the present invention provides a computer program product including computer instructions that, when executed by a processor, implement the steps of the aforementioned method.

[0016] The MLSE equalization reception method and apparatus of the present invention can significantly reduce the computational complexity of MLSE equalization without sacrificing equalization performance, thereby meeting the low energy consumption requirements of communication systems.

[0017] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the description and drawings.

[0018] Those skilled in the art will understand that the objectives and advantages achievable with this invention are not limited to those specifically described above, and that the above and other objectives achievable with this invention will become clearer from the following detailed description. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. The components in the drawings are not drawn to scale but are merely illustrative of the principles of the invention. For ease of illustration and description of certain parts of the invention, corresponding portions in the drawings may be enlarged, i.e., may appear larger relative to other components in an exemplary device actually manufactured according to the invention. In the drawings: Figure 1 This is a flowchart illustrating the MLSE equalization reception method in one embodiment of the present invention; Figure 2 This is a schematic diagram of the signal transmission process in one embodiment of the present invention; Figure 3 This is a schematic diagram of five possible temporary state transitions corresponding to the signal state of 3 or -3 at the previous moment under PAM4 modulation in one embodiment of the present invention. Figure 4 This is a schematic diagram of five possible temporary state transitions corresponding to the signal state of 1 or -1 at the previous moment under PAM4 modulation in one embodiment of the present invention. Figure 5 This is a flowchart illustrating a specific example of the MLSE equalization reception method in one embodiment of the present invention. Figure 6 The simplified MLSE equalization reception method of the present invention and the traditional MLSE equalization reception method are compared in this invention. A diagram showing the comparison of bit error rates under the given conditions. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0021] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0022] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0023] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0024] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0025] To address the issue of high computational complexity in traditional MLSE (Maximum Likelihood Sequence Estimation) equalization algorithms while improving performance, this invention proposes a simplified MLSE equalization receiving method and apparatus. By simplifying the computational steps of signal sequence detection, computational complexity can be reduced without sacrificing equalization performance, effectively solving the problem of high complexity in traditional MLSE equalization algorithms.

[0026] Figure 1 This is a flowchart of an MLSE equalization reception method according to an embodiment of the present invention. See [link / reference] Figure 1 The method includes the following steps: Step S110: Receive the signal to be recovered formed by the signals transmitted at various times. The signal to be recovered is obtained by channel transmission and noise addition to the transmitted signals.

[0027] See Figure 2 , for sending signals conduct Channel transmission and the addition of white Gaussian noise (AWGN) Subsequently, the signal to be recovered was obtained, which had severe inter-symbol interference, or even whose entire sequence was interfered with. for: The receiving end, upon receiving this signal, cannot obtain any valid or accurate information from it. Represents the channel coefficient. , This represents the unit delay operator. After the signal is transmitted... After channel transmission, the signal is obtained. for: , Indicates the signal state at each moment. This indicates the signal state at the previous moment. The transmitted signal is pre-modulated at the transmitting end, and the modulation method includes pulse amplitude modulation (PAM). PAM includes formats such as PAM2, PAM4, and PAM8, where each symbol transmits 1-3 bits of information. PAM4 is a modulation technique that transmits signals (00, 01, 10, 11) through four different voltage levels, transmitting 2 bits of data per symbol period, with signal states including ±3 and ±1. PAM2 uses two voltage levels to represent data (0 and 1), transmitting 1 bit of information per symbol period. This invention mainly uses PAM4 as an example to describe the implementation process of its method in detail. For PAM4, This means that there are four possible signal states at any given time. The signal to be recovered can also be referred to as a multi-rate subcarrier modulated signal.

[0028] Step S120: For each time moment, compare the state metrics of each possible signal state from the previous time moment to the signal state at the current time moment, determine the target state transition path from the previous time moment signal state to the current time moment when the state metric is maximum, and determine the signal state of the previous time moment when the state metric is maximum as the maximum possible signal state of the previous time moment. Each possible signal state is determined based on the modulation method of the transmitted signal, each state metric is updated based on the state metrics of each possible signal state at the previous time moment and the corresponding state transition metrics, and each state transition metric is obtained based on the signal to be recovered, the channel coefficient, each possible signal state at the previous time moment and the signal state at the current time moment.

[0029] Before performing this step, after receiving the multi-rate subcarrier modulated signal, the signal is first converted from analog to digital to obtain a digital signal.

[0030] In this invention, the calculation method for the state metric and the state transition metric can be achieved by processing the signal to be recovered and the transmitted signal. The Euclidean distance between signals transmitted through the channel is simplified and obtained by expansion. Specifically, the signal to be recovered... and signal The Euclidean distance between them can be expanded as (1): in, This represents the number of time points. The square term of the signal to be recovered, which is a common term in the above formula, is also included. Discard the term and divide the remainder by -2 to obtain the state metric. It can be represented as (2): The state transition metric can be obtained by taking one term from the cumulative sum of the state metrics. This state transition metric represents the signal state at the previous time step. Transition to the signal state at the current moment The state transition metric can be expressed as (3): Furthermore, the state metric can ultimately be expressed as (4): This formula represents the signal state at the previous moment. Transition to the signal state at the current moment The state metric is the state metric of the signal state at the current moment.

[0031] This invention selects the state transition path with the minimum Euclidean distance as the survival path or the target state transition path. By observing the relationship between the Euclidean distance and the state metric in the above Euclidean distance formula, it can be found that when the state metric... When the maximum value is taken, the Euclidean distance is minimized. Therefore, in order to accurately recover the received signal and improve equalization performance, this invention determines the signal state of each time step from the signal state of the previous time step that is most likely to transition to the current signal state. Taking PAM4 as an example, the maximum value of the state metric can be expressed as: in, The signal state at the current moment. The state metric for the signal state at the current moment. This is the state metric for signal state 3 at the previous moment. The signal state transition metric between two consecutive time points, specifically the signal state 3 from the previous time point to the current time point. The transition metric is determined by comparing the differences among the four possible state metrics. The maximum value of the state metric is then used to identify the signal state from the previous time step that is most likely to transition to the current signal state. To find the maximum state metric, this invention employs a multi-level difference comparison method.

[0032] In some embodiments, the state metrics of each possible signal state at the previous time step to the signal state at the current time step are compared to determine the target state transition path from the previous time step to the signal state at the current time step when the state metric is maximized. The signal state at the previous time step when the state metric is maximized is determined as the most possible signal state at the previous time step. This includes the following steps: The state metrics of each possible signal state from the previous moment to the current moment are grouped in pairs, and the difference between the two state metrics of each group is compared to determine the signal state of the previous moment when the state metric of each group is larger. The state metrics of the signal state at the previous moment when the state metric of each group is larger are compared pairwise to determine the target state transition path from the signal state at the previous moment when the state metric is larger to the signal state at the current moment, and the signal state at the previous moment when the state metric is larger. The signal state at the previous time step is determined as the maximum possible signal state at the previous time step, so as to obtain the maximum possible signal state at each time step.

[0033] For PAM4, the signal state at each time step If we trace back to the previous moment, its signal state might be: or The maximum state metric is found by comparing the differences between two layers, thus determining the signal state of the previous time step that is most likely to transition to the signal state at each time step. For other modulation schemes such as PAM2 and PAM8, the number of comparison layers can be adjusted accordingly. For PAM4, the two-layer comparison approach is as follows: Specifically, the first-level comparison refers to comparing the state metrics from the previous signal state 3 and -3 to the current signal state in one group to obtain the previous signal state with the larger state metric, and comparing the state metrics from the previous signal state 1 and -1 to the current signal state in another group to obtain the previous signal state with another larger state metric. The second-level comparison refers to comparing the two larger state metrics generated in the first level to obtain the previous signal state with the largest state metric. The path from this previous signal state to the current signal state is the surviving path. In other embodiments, in the first-level comparison, 3, 1, or -1 can also be compared in one group first, and then -3, -1, or 1 can be compared in another group.

[0034] In some embodiments, the state metrics that transfer the possible signal states from the previous time step to the signal state at the current time step are grouped pairwise, and the differences between the two state metrics in each group are compared to determine the signal state in the previous time step when the state metric of each group is larger. This includes the following steps: The state metrics that transfer the signal state from the previous time step to the current time step are grouped into pairs, and the difference between the two state metrics in each group is calculated to obtain the difference between the two state metrics in each group. Based on the correspondence between the difference between the state metrics of the two possible signal states at the previous time and the signal state at the current time and the state transition conditions, determine each first state transition condition corresponding to the difference between the two state metrics of each group. Based on the mapping relationship between state transition conditions and state transition paths, determine each state transition path corresponding to each first state transition condition. Based on each state transition path, determine the signal state of the previous moment when the state metric of the signal state transitioning to the current moment is larger.

[0035] The following explanation, using PAM4, derives and illustrates the two relationships involved in the first-level comparison: Transition the signal state 3 from the previous moment to the signal state at the current moment. State measurement The signal state transitions from the previous time step -3 to the current time step. State measurement Perform a difference comparison. To obtain the signal state 3 and -3 from the previous moment and transition to the signal state at the current moment. The larger state measure, its difference expression is: in, ,Right now This is represented as the difference between the signal state 3 and the state metric of -3 at the previous moment. See also... Figure 3 In the above expression Corresponding as Figure 3 The five intervals shown When located in the interval ,Right now At that time, there were: It can be seen that state measurement , , and It is a relatively large value. That is to say, within the number line interval... In this context, the signal state has a high probability of transitioning from -3 in the previous time step to 3, 1, -1, or -3 in the current time step. Therefore, the state transition paths are -3→3, -3→1, -3→-1, and -3→-3, as follows: Figure 3 middle section The corresponding state transition path diagram is shown below, and the corresponding state transition conditions are: Similarly, it can be deduced that... Figure 3 The other four intervals The state transition path and state transition conditions, specifically, within the interval In the diagram, the state transition paths are -3→3, -3→1, -3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, -3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 3→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... .

[0036] Therefore, the signal states 3 and -3 from the previous moment transition to the signal state at the current moment. State measurement and The difference between them corresponds to the five possible state transition conditions mentioned above, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0037] Transition the signal state from the previous moment (1) to the current moment (2). State measurement The signal state transitions from the previous time step's signal state -1 to the current time step's signal state. State measurement Perform a difference comparison. To obtain the signal state 1 and -1 from the previous moment and transition to the signal state at the current moment. The larger state measure, its difference expression is: in, , This is represented as the difference between the signal state 1 and -1 at the previous time step. See also... Figure 4 In the above expression Corresponding as Figure 4 The five intervals shown When located in the interval ,Right now At that time, there were: It can be seen that state measurement , , and It is a relatively large value. That is to say, within the number line interval... In this context, the signal states are those with a high probability of transitioning from -1 in the previous time step to states 3, 1, -1, and -3 in the current time step, resulting in state transition paths -1→3, -1→1, -1→-1, and -1→-3, as follows: Figure 4 middle section The corresponding state transition path diagram is shown below, and the corresponding state transition conditions are: Similarly, it can be deduced that... Figure 4 The other four intervals The state transition path and state transition conditions, specifically, within the interval In the diagram, the state transition paths are -1→3, -1→1, -1→-1, and 1→-3, and the state transition conditions are... ; in the interval In the given code, the state transition paths are -1→3, -1→1, 1→-1, and 1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, 1→1, 1→-1, and 1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 1→1, 1→-1, and 1→-3, and the state transition conditions are... .

[0038] Therefore, similarly, the signal states 1 and -1 from the previous moment transition to the signal state at the current moment. State measurement and The difference between them corresponds to the five possible state transition conditions mentioned above, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0039] In some embodiments, the state metrics of the signal state at the previous time step when the state metric of each group is larger are compared pairwise to determine the target state transition path from the signal state at the previous time step when the state metric is largest to the signal state at the current time step, and the signal state at the previous time step when the state metric is largest. This includes the following steps: For each group with a larger state metric, the state metric from the previous time step to the current time step is transferred by pairwise subtraction to obtain the difference between each pair of larger state metrics. Based on the correspondence between the difference between the state metrics of the two possible signal states transitioning to the signal state at the previous time and the state transition conditions, determine each second state transition condition corresponding to the difference between each of the two larger state metrics. By combining each first state transition condition and each second state transition condition, we obtain the state transition combination condition. Based on a preset lookup table, a state transition path matching the state transition combination conditions is determined, and the determined state transition path is used as the target state transition path. The lookup table includes multiple state transition combination conditions and multiple corresponding state transition paths. Based on the target state transition path, determine the signal state at the previous moment when the state metric of the signal state transitioning to the current moment is maximized.

[0040] Continuing with the derivation and explanation of the relationships involved in the second-level comparison: In the first-level comparison, the larger state metric in one set is likely the signal state 3 that transitioned from the previous time step to the current time step. State measurement Alternatively, the signal state from the previous moment -3 transitions to the signal state at the current moment. State measurement The larger state metric in the other group could be the signal state 1 from the previous time step to the current time step. State measurement Alternatively, the signal state from the previous moment -1 transitions to the signal state at the current moment. State measurement Therefore, a larger state metric is used. and another larger state metric To obtain the maximum state metric, a difference comparison is performed. The difference expression is as follows: in, ,Right now This is represented as the difference between the signal states 3 and -1 at the previous time step. Following a derivation process similar to the first layer, five intervals can be deduced. The corresponding five possible state transition paths and state transition conditions: within the interval In the diagram, the state transition paths are 3→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, -1→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, -1→1, -1→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, -1→1, -1→-1, and -1→-3, and the state transition conditions are... .

[0041] That is, similarly, the signal states 3 and -1 from the previous moment transition to the signal state at the current moment. State measurement and The difference between them corresponds to the five possible state transition conditions, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0042] Larger state metrics and another larger state metric To obtain the maximum state metric, a difference comparison is performed. The difference expression is as follows: in, ,Right now This is represented as the difference between the state metrics of signal states 3 and 1 at the previous time step. Similarly, five intervals can be obtained. The corresponding five possible state transition paths and state transition conditions: within the interval In the diagram, the state transition paths are 3→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 3→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 1→1, 3→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 1→1, 1→-1, and 3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 1→1, 1→-1, and 1→-3, and the state transition conditions are... .

[0043] That is, similarly, the signal states 3 and 1 from the previous moment transition to the signal state at the current moment. State measurement and The difference between them corresponds to the five possible state transition conditions, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0044] Larger state metrics and another larger state metric To obtain the maximum state metric, a difference comparison is performed. The difference expression is as follows: in, ,Right now This is represented as the difference between the state metrics of the signal states -3 and -1 at the previous time step. Similarly, five intervals can be obtained. The corresponding five possible state transition paths and state transition conditions: within the interval In the diagram, the state transition paths are -3→3, -3→1, -3→-1, and -3→-3, and the state transition conditions are... ; in the interval In the given code, the state transition paths are -3→3, -3→1, -3→-1, and -1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, -3→1, -1→-1, and -1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, -1→1, -1→-1, and -1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -1→3, -1→1, -1→-1, and -1→-3, and the state transition conditions are... .

[0045] Similarly, the signal states -3 and -1 from the previous time step transition to the signal state at the current time step. State measurement and The difference between them corresponds to the five possible state transition conditions, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0046] Larger state metrics and another larger state metric To obtain the maximum state metric, a difference comparison is performed. The difference expression is as follows: in, ,Right now This is represented as the difference between the signal states -3 and 1 at the previous time step. Similarly, five intervals can be obtained. The corresponding five possible state transition paths and state transition conditions: within the interval In the diagram, the state transition paths are -3→3, -3→1, -3→-1, and -3→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, -3→1, -3→-1, and 1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, -3→1, 1→-1, and 1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are -3→3, 1→1, 1→-1, and 1→-3, and the state transition conditions are... ; in the interval In the diagram, the state transition paths are 1→3, 1→1, 1→-1, and 1→-3, and the state transition conditions are... .

[0047] Similarly, the signal states -3 and -1 from the previous time step transition to the signal state at the current time step. State measurement and The difference between them corresponds to the five possible state transition conditions, and there is a one-to-one correspondence between the five possible state transition conditions and the five possible state transition paths.

[0048] The various possible state transition conditions obtained from the first-level comparison and the second-level comparison are combined, and the various possible state transition paths are also combined to obtain a preset look-up table (LUT), as shown in Table 1. In Table 1, in the transition path column, taking number 1 as an example, its transition path [-3,-3,-3,-3] represents the path from the previous signal state -3 to the current signal states -3, -1, 1, and 3 respectively.

[0049] Table 1 In other embodiments, the difference comparisons for other cases in the first-level comparison and the second-level comparison can also be derived using the same principles as in the derivation process of the above embodiments to obtain the corresponding correspondence, mapping relationship and lookup table.

[0050] Step S130: Based on the target state transition path at each time step, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of the possible signal states at the last time step, determine the equalization signal corresponding to the signal to be recovered.

[0051] In some embodiments, the equalization signal corresponding to the signal to be recovered is determined based on the target state transition path at each time step, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of the possible signal states at the last time step. This includes the following steps: Based on the target state transition path at each time step and the signal state corresponding to the maximum state metric among the state metrics of each possible signal state at the last time step, the final signal state of the previous time step is determined by backtracking from the maximum possible signal state of the previous time step at each time step. Based on the final signal state of the previous time step and the signal state corresponding to the maximum state metric of the last time step, the equalization signal corresponding to the signal to be recovered is obtained.

[0052] In some embodiments, the method further includes the following steps: If the number of determined signal states reaches a preset backtracking depth, an intermediate equalization signal is output. The process of determining signal states continues until a final equalization signal is output. The intermediate equalization signal is determined by considering the target state transition path at each time step reaching the backtracking depth, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of all possible signal states at the last time step. In this embodiment, different backtracking depths can be set according to different needs.

[0053] In some embodiments, the method further includes the step of: demapping the equalization signal to obtain the corresponding recovery signal.

[0054] For example, see Figure 5 The received signal needs to be processed. Channel transmission and AWGN signals to be recovered The process of achieving balanced reception includes: Step S1: Receive the signal to be recovered or the signal to be detected. ,set up ,when During initialization , , , , , and If both are 0, then ; Step S2-1: When At that time, the first level comparison: transfer the signal state 3 from the previous time step to the signal state at the current time step. The state metric and the signal state from the previous time step -3 transition to the signal state at the current time step. The state metrics are compared, that is, the calculations are performed. The value, let this value belong to If the interval is defined, then the first state transition condition is determined as follows: ,pass The state transition path of the interval can determine the signal state at the current moment. It is highly likely that they all transitioned from the signal state-3 of the previous moment; Transition the signal state from the previous moment (1) to the current moment's signal state. The state metric and the signal state from the previous time step -1 transition to the signal state at the current time step. The state metrics are compared, that is, the calculations are performed. The value, let this value belong to If the interval is defined, then the first state transition condition is determined as follows: ,pass The state transition path of the interval can determine the signal state at the current moment. It is highly likely that they are transitioned from the signal state -1 of the previous time step, as well as the signal state of the current time step. It is highly likely that they all transitioned from signal state 1 in the previous moment; Step S2-2: Second-level comparison: Transition the signal state -3 from the previous time step with the larger state metric to the signal state at the current time step. The signal state transitioning from the previous time step -1 to the current time step with the larger state metric is... The state metrics are compared, that is, the calculations are performed. The value, let this value belong to If the interval is defined, then the condition for the second state transition is determined as follows: ; Transition the signal state -3 from the previous time step with the larger state metric to the signal state at the current time step. The signal from the previous time step with a larger state metric (state 1) transitions to the current time step. The state metrics of the signal state are compared, that is, the calculation is performed. The value, let this value belong to If the interval is defined, then the condition for the second state transition is determined as follows: ; Step S3: Combine the two first state transition conditions obtained in step S2-1 and the two second state transition conditions obtained in step S2-2 to obtain the fourth state transition combination condition in lookup table 1, and determine the target state transition path as [-3, -3, -1, -1]. This allows for further determination of the signal state at the current moment. Most likely, they all transitioned from the signal state -3 of the previous time step, as well as the signal state of the current time step. Most likely, they all transitioned from the signal state -1 of the previous moment; Step S4: Calculate and update the state transition metric according to equations (3) and (4). and state metrics , ; Step S5: If the backtracking depth has not been reached, repeat steps S2-1 to S4 until the backtracking depth is reached; repeat step S5 until the final equalization signal corresponding to the signal to be recovered is output. Step S6: Select the signal state with the largest state metric among all possible signal states at the last moment, and backtrack through the target state transition paths or surviving paths determined in previous moments to output an equalized signal. Demap the equalized signal to obtain the recovered bit sequence. For example, if the target state transition path is determined to be [-3,-3,-1,-1] at the second moment, [-3,-1,-1,-3] at the third moment, and [-3,-3,-1,-3] at the fourth moment (the last moment), and if among the four possible signal states at the last moment... State measurement If the maximum value is found, then the final output equalized signal is determined to be {-3,-1,-1,1}.

[0055] Taking PAM4 as an example, the traditional MLSE equalization reception method requires 16 multiplication operations to obtain the target state transition path. Since the traditional state transition path diagram has 16 paths, specifically -3→3 / 1 / -1 / -3, -1→3 / 1 / -1 / -3, 1→3 / 1 / -1 / -3, and 3→3 / 1 / -1 / -3, meaning the traditional MLSE compares 16 paths, these 16 multiplication operations include all 16 multiplication operations involved in those 16 paths. The simplified MLSE equalization reception method in this invention requires only 5 multiplication operations to obtain the target state transition path. These 5 multiplication operations include 1 multiplication operation involved in determining the state transition conditions and 4 multiplication operations involved in updating the state transition metric of the four possible signal states from the previous time step to the current time step. As can be seen, compared with the traditional MLSE algorithm, the number of multiplication operations required by the present invention in the entire equalization reception process is greatly reduced, which can significantly reduce the computational complexity of MLSE equalization, thereby meeting the low energy consumption requirements of communication systems.

[0056] See Figure 6 According to Under the given conditions, the bit error rate diagrams of the simplified MLSE equalization reception method and the traditional MLSE equalization reception method in this invention show that their equalization performance is consistent. Furthermore, it can be concluded that the simplified MLSE equalization reception method proposed in this invention can significantly reduce the computational complexity of MLSE equalization in digital signal processing, and its equalization performance is consistent with that of traditional complex methods. This conclusion can also be drawn for other modulation schemes.

[0057] Corresponding to the above method, the present invention also provides an MLSE equalization receiving device, which includes a computer device including a processor and a memory. The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the device implements the steps of the aforementioned method.

[0058] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the aforementioned method. The computer-readable storage medium may be a tangible storage medium, such as random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, floppy disk, hard disk, removable storage disk, CD-ROM, or any other form of storage medium known in the art.

[0059] This invention also provides a computer program product, including computer instructions that, when executed by a processor, implement the steps of the aforementioned method.

[0060] Those skilled in the art will understand that the exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Whether implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention. When implemented in hardware, it can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the desired tasks. The programs or code segments can be stored in a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave.

[0061] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0062] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An MLSE equalization reception method, characterized in that, The method includes: The signal to be recovered is formed by receiving signals transmitted at various times, wherein the signal to be recovered is obtained by channel transmission and noise addition to the transmitted signals; For each time step, the state metrics of each possible signal state from the previous time step to the signal state at the current time step are compared to determine the target state transition path from the previous time step to the signal state at the current time step when the state metric is maximized. The signal state of the previous time step when the state metric is maximized is determined as the maximum possible signal state of the previous time step. Each possible signal state is determined based on the modulation scheme of the transmitted signal. Each state metric is updated based on the state metrics of each possible signal state at the previous time step and the corresponding state transition metrics. Each state transition metric is obtained based on the signal to be recovered, the channel coefficient, each possible signal state at the previous time step, and the signal state at the current time step. Based on the target state transition path at each time step, the maximum possible signal state at the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of the possible signal states at the last time step, the equalization signal corresponding to the signal to be recovered is determined.

2. The MLSE equalization reception method according to claim 1, characterized in that, The process involves comparing the state metrics of each possible signal state from the previous time step to the current time step, determining the target state transition path from the previous time step to the current time step when the state metric is maximized, and identifying the signal state from the previous time step when the state metric is maximized as the most possible signal state from the previous time step. This includes: The state metrics of each possible signal state from the previous moment to the current moment are grouped in pairs, and the difference between the two state metrics of each group is compared to determine the signal state of the previous moment when the state metric of each group is larger. The state metrics of the signal state at the previous moment when the state metric of each group is larger are compared pairwise to determine the target state transition path from the signal state at the previous moment when the state metric is larger to the signal state at the current moment, and the signal state at the previous moment when the state metric is larger. The signal state at the previous time step is determined as the maximum possible signal state at the previous time step, so as to obtain the maximum possible signal state at each time step.

3. The MLSE equalization reception method according to claim 2, characterized in that, The state metrics for transferring the possible signal states from the previous time step to the current time step are grouped pairwise. The differences between the two state metrics in each group are compared to determine the signal state from the previous time step when the state metric of the group with the larger value is used. This includes: The state metrics that transfer the signal state from the previous time step to the current time step are grouped into pairs, and the difference between the two state metrics in each group is calculated to obtain the difference between the two state metrics in each group. Based on the correspondence between the difference between the state metrics of the two possible signal states at the previous time and the signal state at the current time and the state transition conditions, determine each first state transition condition corresponding to the difference between the two state metrics of each group. Based on the mapping relationship between state transition conditions and state transition paths, determine each state transition path corresponding to each first state transition condition. Based on each state transition path, determine the signal state of the previous moment when the state metric of the signal state transitioning to the current moment is larger.

4. The MLSE equalization reception method according to claim 3, characterized in that, For each group with a larger state metric, the state metrics from the previous time step to the current time step are compared pairwise to determine the target state transition path from the previous time step with the largest state metric to the current time step, and the previous time step with the largest state metric, including: For each group with a larger state metric, the state metric from the previous time step to the current time step is transferred by pairwise subtraction to obtain the difference between each pair of larger state metrics. Based on the correspondence between the difference between the state metrics of the two possible signal states transitioning to the signal state at the previous time and the state transition conditions, determine each second state transition condition corresponding to the difference between each of the two larger state metrics. By combining each first state transition condition and each second state transition condition, we obtain the state transition combination condition. Based on a preset lookup table, a state transition path matching the state transition combination conditions is determined, and the determined state transition path is used as the target state transition path. The lookup table includes multiple state transition combination conditions and multiple corresponding state transition paths. Based on the target state transition path, determine the signal state at the previous moment when the state metric of the signal state transitioning to the current moment is maximized.

5. The MLSE equalization reception method according to claim 1 or 4, characterized in that, Based on the target state transition path at each time step, the maximum possible signal state of the previous time step, and the signal state corresponding to the maximum state metric among the state metrics of all possible signal states at the last time step, the equalization signal corresponding to the signal to be recovered is determined, including: Based on the target state transition path at each time step and the signal state corresponding to the maximum state metric among the state metrics of each possible signal state at the last time step, the final signal state of the previous time step is determined by backtracking from the maximum possible signal state of the previous time step at each time step. Based on the final signal state of the previous time step and the signal state corresponding to the maximum state metric of the last time step, the equalization signal corresponding to the signal to be recovered is obtained.

6. The MLSE equalization reception method according to claim 1, characterized in that, The method further includes: If the number of determined signal states reaches a preset backtracking depth, an intermediate equalization signal is output, and the process of determining signal states continues until the final equalization signal is output. The intermediate equalization signal is determined by the signal state corresponding to the maximum state metric among the target state transition paths at each time step reaching the backtracking depth, the maximum possible signal state at the previous time step, and the state metrics of the possible signal states at the last time step.

7. The MLSE equalization reception method according to any one of claims 1 to 4 and 6, characterized in that, The signal states at each time point include all possible signal states, and the modulation method includes pulse amplitude modulation. The state metric and the state transition metric are calculated by simplifying the Euclidean distance expansion between the signal to be recovered and the transmitted signal obtained through channel transmission.

8. The MLSE equalization reception method according to any one of claims 1 to 4 and 6, characterized in that, The method further includes: demapping the equalization signal to obtain the corresponding recovery signal.

9. An MLSE equalization receiving device, comprising a processor, a memory, and computer instructions stored in the memory, characterized in that, The processor is configured to execute the computer instructions, and when the computer instructions are executed, the system implements the steps of the method as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method as described in any one of claims 1 to 8.

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